Insert for grinding wheels



y 7, 1958 R. L. TYGH 2,836,017

INSERT FOR GRINDING masts Filed Aug. 26, 1955 INVENTOR ROBERT L. TVGH ATTORNEY United States Patent INSERT FOR GRINDING WHEELS Robert L. Tygh, Jackson, Mich.

Application August 26, 1955, Serial No. 530,820

4 Claims. (Cl. 51-209) The present invention relates to grinding wheels and inserts therefor, and more particularly to new and improved inserts for grinding wheels which will serve as reinforced attachment elements by which the wheel may be detachably secured to a grinding machine.

It is an object of the present invention to provide grinding wheels having attachment inserts which will not break loose from the wheel in use. 7

Another object of the invention is to provide grinding wheels which may be quickly attached to and detached from a grinding machine.

The invention also contemplates providing grinding wheels having attachment inserts, which may be easily formed with the inserts in place.

A further object of the invention is the provision of inserts for grinding wheels which will be simple and inexpensive to manufacture but which will be rugged and durable in use.

Other objects and advantages will become apparent from the following description taken in conjunction with the accompanying drawing, in which:

Figure 1 is a fragmentary plan view of a grinding Wheel according to my invention, as seen from the attachment side;

Figure 2 is an enlarged fragmentary sectional view on the line 2-2 of Figure 1;

Figure 3 is a perspective view of a first embodiment of grinding wheel insert according to my invention; and

Figure 4 is a view similar'to Figure 3 but showing another embodiment of insert according to my invention.

Referring now to the drawings in greater detail, I have shown in Figure l a fragmentary plan view of a portion of a grinding wheel 1 comprising an annular body member which may be in the form of a flat annular disc as shown in Figures 1 and 2, or which may be in the form of an annular cup or other common configuration for grinding wheels. Grinding wheels of this type are generally bonded of synthetic resins, rubber, shellac, or other like materials suitable for forming a hard matrix of particles of abrasives; and Figure 2 is hatched to indicate abrasive bonded with such materials.

Means are provided for removably attaching the grinding wheel to the backing plate of a grinding machine so that spent wheels may be quickly and easily removed and replaced by a fresh wheel. To this end, reinforcing attachment elements comprising inserts 3 are molded in the back face of the wheel. According to a first embodiment of my invention, and perhaps as best seen in Figure 3, each insert comprises a substantially flat web portion 5 provided with a pair of edge flanges 7 along opposite longitudinal sides thereof. Both flanges '7 are disposed on the same side of the plane of web portion 5 and are comprised of generally perpendicular portions 9 adjacent web portion 5, followed by outwardly inclined portions 11 terminating in edges 13 which are spaced apart a distance greater than the width of web portion 5.

For the purpose of attachment to a grinding machine, the web portion is provided with a centrally located hole 2,836,017 Patented May 27, 1958 "ice.

15 and an outstanding boss 17 on the same side of the web portion as the flanges 7. Boss 17 is fitted snugly between perpendicular portions 9, and for this purpose is provided with a pair of parallel side edges 19 which are perpendicular to web portion 5. Boss 17 is also provided with an internally screw-threaded opening 21 in registry with hole 15.

In the embodiment'of Figure 3, boss 17 is integral with the rest of insert 3. Such an assembly may be manufactured by inserting boss 17 between perpendicular portions 9 and then punching opposite sides of portions 9 as shown at 22 so as firmly to grip the boss in place.

Grinding wheels according to this embodiment of the invention may be manufactured as follows:

A plurality of inserts 3 may be placed in the bottom of a wheel mold and located on rotatably mounted screwthreaded studs projecting from the bottom of the mold. The abrasive molding composition may be then introduced into the body of the mold to fill up the mold and fill in around the inserts 3. After hardening, the rotatable screw-threaded studs may then be withdrawn and the finished product removed from the mold. The Withdrawn studs will have maintained openings 21 free from molding composition, as seen in Figure 2. It will also be noted that the outer face of web portion 5 will be flush with the adjacent side face 23, which is the underside or attachment side of the wheel.

In operation, grinding wheels according to the invention may simply be placed against the back plate or wheel plate of a grinding machine and screw-threaded bolts introduced through the plate and screwed into openings 21. In this way, the grinding wheel is firmly but detachably held against the plate. It will also be noted that the divergent edge flanges 7 will lock the inserts within the body of the molded material. Moreover, the fact that the inserts are substantially extended beyond bosses 17 on either side thereof assures that the strain of the attachment members will be transmitted to the bonded material of the grinding wheel over a very much enlarged area, so that the wheel is much less likely to fracture in use.

In Figure 4, I have shown a second embodiment of insert according to my invention, comprising an insert 3 including a medial web portions provided with a pair of edge flanges 7' commencing with perpendicular portions 9 and extending to outwardly inclined divergent portions 11 terminating in edges 13 spaced apart a distance greater than the Width of the web portion. As before, a centrally located hole 15 is provided in web portion 5; but no integral boss is included. According to the embodiment of Figure 4, the insert assembly is comprised of a separate insert 3' and boss similar to the boss of the embodiment of Figure 3, there being no attempt to fix the two together integrally as in Figure 3. Thus, the embodiment of Figure 4 when assembled in a completed grinding wheel has the same appearance indicated in Figure 2 but the method of assembly is slightly different in that the boss is placed in registry with hole 15 at the time of assembly.

It will be noted that grinding wheel inserts according to my invention are extremely simple in construction and easy to manufacture and install. It should also be noted that the broad extent over which the strain between the attachment members and the grinding wheel is spread assures that the grinding wheel will not likely be fractured or damaged in installation or use. Moreover, it will be obvious that inserts according to my invention, formed in the manner disclosed above and set in the rear face of the grinding wheel, provide a maximum of useful thickness of grinding wheel. In most cases, most of the thickness of the wheel can be consumed in grinding operations before it is necessary to replace the wheel. Finally, it will be obvionsjthat grinding wheels according to my invention are extremely easy to attach and detach to grinding machines, since the attachment members may comprise standard size bolts.

Thus, it will be clear that I have achieved all of the objects of my invention. Although the present invention-has conjunction with preferred embodiments, it is to be understood that modifications and variations may be resorted to withoutdeparting from :the spirit and scopeoftheinvention, as those skilled in the art will readily understand. Such modifications and variations are considered to be within the purview:and scope of the invention and appended claims.

I claim: I V v n 1. An insert fora grinding Wheel comprisinga channel member having a 'WBb portion and a pair of parallel edge flanges, said web portion having .a holecentrally thereof been described in flanges held snugly between the perpendicular portions of said flanges, said boss also having a screw-threaded opening therethrough in registry with said hole. 7

3. A grinding Wheel comprising an annular body'memher and at least one insert embedded in a side face of said member, said insert having a web portion disposed substantially flush in said side face, said web portion having a hole centrally thereof, said insert also having a pair of parallel 'edge'flanges extending perpendicularly into said body memberand terminating in edges spaced apart a distance greater than the width of said w eb portion, and a nut on the same side "of said Web portion'as said flanges, said nut having ascrew-threaded opening therethrough in registry with said hole, said nut having parallel sides emand said edge flanges terminating in, edges spaced apart .7

a distance greater than the width of said web portion, and

a nut abutting saidweb andsnuglyconfined between edge flanges, said nut having parallel sides'v'engaged between said parallel edge flanges, and said nut having athr'eaded hole in registry with said first hole, said edge flanges. retainingsaid nut against relative rotation insaid insert; and said edge flanges restraining said insert against relative rotation in the grinding wheel. V V

2. An insert for a grinding wheel comprisinga channel member having a web portion and apair'of parallel edge flanges, said Web portion having a hole centrally thereof, said'edge flanges extending from said web portion perpendicular thereto and thereafter diverging .away from each other, and a boss on the same sideof said web portion as said flanges, said boss having a pair of side'edges perpendicular to said web portion and parallel to said edge braced between said edge flanges and held against relative rotation thereby. a V

4. A grinding wheel comprising an annular body memher and at least one insert embedded in a side face of said edge flanges extending from said Webportion perpendicu-' lar thereto and into said body member and thereafter diverging away from eachother, and a boss on the same side of said web portion as said flanges, said boss having a pair of side edges perpendicular to said web portion held snugly between the perpendicular portions of said flanges, w

said boss also having a screw-threaded opening therethrough in registry with saidhole.

References'Cited in the file of this patent UNITED STATES PATENTS 2,351,129 Jockel June 13, 1944 Doermann Aug. 12, 1947- 

